A Flashboard Riser, or weir box, is an overflow-type dam. 

Our Flashboard Risers form a collar around a corrugated steel drainage pipe that exerts a strong clamping force by its multiple take up points. Our risers use standard 2x4" lumber for dam boards, readily available from any lumber company, or you can choose to have them included in your order at an additional cost. 

This Flashboard Riser is fabricated to fit a 18" Corrugated Steel Culvert.

If you do not have a 18" culvert see other sizing options, if your culvert size is not listed please call for availability and pricing!